In accordance with conventional practice, railway track structure comprises a bed of ballast, a plurality of equi-spaced wooden cross ties resting on the ballast, and a pair of parallel rails secured to and supported on the upper surface of the ties. The rails are fastened to the ties by means of spikes or other conventional retainers.
When a section of railway track is subjected to traffic, the repeated passage and weight of the train causes the underlying ballast, usually composed of gravel, to become displaced under portions of the ties. In most instances, the ballast directly beneath the rails and the ends of the ties will be displaced more than the ballast near the center of the ties. In such a case, greater stress is placed on the center of the tie, which may cause the tie to crack in the middle. In other instances, the weight of the train causes the end of the tie to become split or cracked, thereby seriously weakening the track structure. Proper track maintenance requires that cracked or split ties be replaced with regularity, which is a costly and time consuming process.
The laying of track according to the conventional procedure is complicated by the need to obtain as much uniformity as possible. Particularly, the uniform spacing of the ties is critical, and time consuming measurement procedures must be utilized.
Typical rail and tie support arrangements in the prior art include rigid concrete structures as well as metallic pedestals for supporting a rail, wherein the tie is either clamped within or otherwise rigidly affixed to the pedestal. These arrangements are inadequate to overcome the problem of deterioration of the cross tie or concrete support, since the vertical flexing of the rail during passing of the train tends to concentrate stresses in these rigid structures. In the case of the pedestal, vertical movements on the rail may cause undue compression of the tie, displacement of ballast and lifting of the pedestal from the ballast. In the case of these rigid concrete structures, cracking and failure has been encountered.